Device for securing a furnace head to the housing of an electrothermal furnace

ABSTRACT

Device for securing a furnace head to the housing of an electrothermal furnace, for example a calcium carbide furnace, wherein the upper rim portion of the furnace housing is arranged to be encircled by a cantilever receiving a layer of insulating bricks to provide support for the water-cooled furnace head. The furnace head is more particularly designed to have a cantilever running parallel to an opposed cantilever fast with the furnace housing, whereby the cantilever secured to the furnace housing and that secured to the furnace head are both arranged to be encircled in a plane common to them by a flange having a ledge secured to it, through interposed insulating material.

United States Patent Hans Drehsen Kendenlch near Koln;

Helmut Ahrens, Kendenich near Koln; Benedikt Georg, Knapsack near Koln; Kurt Zager, GleueI near Koln, all of Germany Inventors Appl. No. 887,533 Filed Dec. 23, 1969 Patented Nov. 23, 1971 Assignee knapsack Aktiengesellschaft Knapsack bel Koln, Germany Priority Dec. 23, 1968 Germany DEVICE FOR SECURING A FURNACE HEAD TO THE HOUSING OF AN ELECTROTHERMAL FURNACE 10 Claims, 8 Drawing Figs.

[56] References Cited UNITED STATES PATENTS 855,476 6/1907 Price 13/32 1,992,465 2/1935 Blagg 13/32 X 2,648,714 8/1953 Williams et alt 263/44 X Primary Examiner--.Iohn J. Camby A!lorney-Connolly and Hutz ABSTRACT: Device for securing a furnace head to the housing of an electrothermal furnace, for example a calcium carbide furnace, wherein the upper rim portion of the furnace housing is arranged to be encircled by a cantilever receiving a layer of insulating bricks to provide support for the watercooled furnace head. The furnace head is more particularly designed to have a cantilever running parallel to an opposed cantilever fast with the furnace housing, whereby the cantilever secured to the furnace housing and that secured to the furnace head are both arranged to be encircled in a plane common to them by a flange having a ledge secured to it. through interposed insulating material.

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sum u 0F 4 DEVICE FOR SECURING A FURNACE HEAD TO THE HOUSING OF AN ELECTRO'I'HERMAL FURNACE The present invention relates to a device for securing a furnace head to the housing of an electrothermal furnace, particularly a reduction furnace, for example a calcium carbide furnace or similar furnace, wherein the upper rim portion of the furnace housing or wall is arranged to be encircled by a cantilever receiving a layer of insulating bricks to provide support for the water-cooled furnace head.

In a conventional device of the type described above, two flanges are provided, of which one is arranged to encircle the upper end of the furnace housing and of which the other is arranged to encircle the lower end of the furnace head, and which are used to rigidly connect the furnace head to the furnace housing, through an interposed layer of insulating bricks. In those cases in which thermal stress effects radial movement of the furnace housing or wall, more particularly in those cases in which temperature variations effect a reduction or enlargement of the diameter of the furnace housing, it is found that the insulating bolts, which rigidly connect the two flanges together, are subject to the action of shearing forces. The reason for this is the inability of the furnace head to expand at a rate consistent with the expansion rate of the furnace housing. In those cases in which the bolts are subject to undue shearing forces, the insulations are rendered inactive and the bolts are sheared off or become electrically destructed. Needless to say the water-cooled furnace head then fails to be satisfactorily secured to the furnace housing naturally with the resultant formation of leakage areas in the 'electrothermal furnace, which are highly undesirable and handicap not only furnace operation itself but also the operating personnel standing close by.

The object of the present invention is to provide a device for securing a furnace head to the housing of an electrothermal furnace. which is free from the disadvantageous phenomena reported above, unsusceptible to shearing forces, enables the transition area between the furnace housing and furnace head to be sealed in gastight fashion and to be perfectly connected together, and finally provides a true duplex insulation. To achieve this, it is substantially necessary for the furnace head to be provided with a cantilever running parallel to an opposed cantilever fast with the furnace housing, whereby the cantilever secured to the furnace housing and that secured to the furnace head are both arranged to be encircled in a plane common to them by a flange having a ledge fastened thereto, through an intermediary layer of insulating material. The device so designed is fully apt to meet the requirements of the present invention. More particularly, the bolts are no longer subject to the action of shearing forces. The reasons for this firstly reside in the fact that they are arranged perpendicularly with respect to the furnace axis, and secondly in the fact that resilient elements are disposed between the furnace housing and the furnace head for those cases in which the bolts are arranged parallel to the furnace axis. In other words, the bolts are no longer subject to shear-off phenomena and the device is and remains gastight. The nonoccurrence of shearing forces also prevents the furnace head from being forced out of its base support under supcrpressure establishing inside the furnace itself. The invention also provides for the arrangement of packing material, which is preferably a combination of asbestos with insulating material, and for the use of insulating bolts, to ensure a true duplex insulation.

The invention further provides for the flanges to have a common vertical plane. This enables the occurrence of shearing forces affecting the bolts, such as those normally occasioned by different thermal stress in the furnace walls, to be avoided with certainty.

A still further feature of the present invention provides for the flanges to have a common horizontal plane. In this case, the furnace head is spring connected to its associated flange with the result that the bolts, which run perpendicularly with respect to the furnace axis, are subject to minor shearing forces only, that can be ignored here.

The invention also provides for the ledge to have a rectan gular cross-sectional area and substantially the same overall thickness.

In accordance with a still further feature of the present invention, it is possible for the ledge lying within the area between the cantilever secured to the furnace housing and that secured to the furnace head, to be made up of resilient or elastic material having a smaller cross section within that area than within the reach of the flanges.

A still further feature of the present invention provides for the area between the cantilever secured to the furnace housing and that secured to the furnace head to be left free from insulating material.

The invention still further provides for the arrangement of a resilient and elastic plate within the area between the cantilever secured to the furnace housing and that secured to the furnace head.

The invention finally provides for the flanges, the insulating intermediary layer and the ledge to be made up of a plurality of parts and to have a polygonal cross-sectional area, seen in the direction of the furnace axis.

The invention will now be described with reference to the accompanying drawings showing some exemplary representations of the present device. In the drawings FIG. I is a rough diagrammatic cross-sectional view of an electrothermal furnace,

FIGS. 2 to 6 represent various modifications of detail A shown in FIG. I, and

FIGS. 7 and 8 are two sectional views taken along the line VII-VII of FIG. I.

The device shown in the accompanying drawings is used for securing furnace head 10 to housing 11 of an electrothermal furnace, more particularly a reduction furnace, e.g. a calcium carbide furnace or a similar furnace, such as that shown diagrammatically in FIG. I. Furnace housing 11 substantially comprises furnace wall 12 of which the sides I3 and the bottom 14 are brick lined l4. Furnace head 10 has ducts for the passage of electrodes therethrough, of which merely one, namely electrode 15, is shown in FIG. I. The invention relates to element 16 which is arranged approximately level with the transition area between furnace wall I2 and furnace head I0.

Details of element I6 are shown in FIG. 2. As can be seen, furnace wall I2, i.e. the upper rim portion thereof, has a cantilever 17 secured to it, which in turn is connected to flange I8. Flange 20 is connected in analogous manner to cantilever 19 of furnace head I0. The two cantilevers I7 and 19 have a layer of insulating bricks 21 placed therebetween and two layers of insulating material 22 and 23 are provided between insulating bricks 21 and cantilever 19 fast with furnace head I0, and between insulating bricks 21 and cantilever I7 fast with furnace wall 12, respectively. Flanges l8 and 20 both have a ledge 25 flanged thereto by means of insulating bolts 26 and 27, through an intermediary layer of insulating material 24.

The device shown in FIG. 3 differs from that shown in FIG. 2 substantially in that flange 25 is made elastic; more particularly ledge 25 is made rigid within the reach of flanges l8 and 20 and elastic and resilient (28) between flanges l8 and 20. The middle portion 28 of the flange is preferably made up of sheet copper.

As shown in FIGS. 4, 5 and 6, flanges 18 and 20 are arranged to lie in a horizontal plane common to both of them. In FIG. 4, ledge 25 is made rigid. The elastic, resilient intermediary part 31 placed between furnace head I0 and its associated flange 20 is arranged to move to position (32) indicated by the broken line in FIG. 4, if the upper portion 12' of furnace wall 12 should actually be found to have moved to that position. This is done to avoid the occurrence of shearing forces.

Similar statements as those made with respect to ledge 25 shown in FIG. 3 are applicable to ledge 25 shown in FIG. 5, save that coherent packing 24 is subdivided here into two partial packings 29 and 30. The expansion which occurs between furnace wall I2 and furnace head 10 is equalized and effected by the ledge's elastic middle portion 28.

HO. 6 shows substantially the same device as FIG. save that the ledge's elastic middle portion 28 is bent in opposite direction.

HO. 7 shows the polygonality of ledge 25, intermediary asbestos layer 24 and flanges 20 and 18, respectively, which all comprise a plurality of parts, as shown in the modifications of FIGS. 7 and 8.

HO. 8 is a side view of element 16 shown in FIGS. 4, 5 and 6, wherein ledge 25, intermediary asbestos layer 24 and flanges 20 and 18, respectively, are all made up of a plurality of parts, without being polygonal.

We claim:

1. A device for securing a furnace head to the housing of an electrothermal furnace, the upper rim portion of the furnace housing being arranged to be encircled by a cantilever receiving a layer of insulating bricks to provide support for the water-cooled furnace head, wherein the furnace head is designed to have a cantilever running parallel to an opposed cantilever fast with the furnace housing, whereby the cantilever secured to the furnace housing and that secured to the furnace head are both arranged to be encircled in a plane common to them by a flange having a ledge fastened thereto, through an intermediary layer of insulating material.

2. A device for securing a furnace head to the housing of a reduction furnace, for example a calcium carbide furnace, the upper rim portion of the furnace housing being arranged to be encircled by a cantilever receiving a layer of insulating bricks to provide support for the water-cooled furnace head, wherein the furnace head is designed to have a cantilever running parallel to an opposed cantilever fast with the furnace housing, whereby the cantilever secured to the furnace housing and that secured to the furnace head are both arranged to be encircled in a plane common to them by a flange having a ledge fastened thereto, through an intermediary layer of insulating material.

3. The device as claimed in claim 1, wherein the flanges are arranged to have a common vertical plane.

4. The device as claimed in claim 1, wherein the flanges are arranged to have a common horizontal plane.

5. The device as claimed in claim 1, wherein the ledge has a rectangular cross-sectional area and substantially the same overall thickness.

6. The device as claimed in claim 1, wherein the ledge is made up of elastic resilient material within the area between the cantilever secured to the furnace housing and that secured to the furnace head, the ledge having a smaller cross section within that area than within the reach of the flanges.

7. The device as claimed in claim 1, wherein the area between the cantilever secured to the furnace housing and that secured to the furnace head is left free from insulating material.

8. The device as claimed in claim 1, wherein a resilient elastic plate is arranged within the area between the cantilever secured to the furnace housing and that secured to the furnace head.

9. The device as claimed in claim 1, wherein the flanges. the insulating intermediary layer and the ledge comprise a plurality of parts and have a polygonal cross-sectional area, seen in the direction of the furnace axis.

10. The device as claimed in claim 1, wherein the flanges. the insulating intermediary layer and the ledge are connected together by means ofinsulating bolts.

* k i t 

1. A device for securing a furnace head to the housing of an electrothermal furnace, the upper rim portion of the furnace housing being arranged to be encircled by a cantilever receiving a layer of insulating bricks to provide support for the watercooled furnace head, wherein the furnace head is designed to have a cantilever running parallel to an opposed cantilever fast with the furnace housing, whereby the cantilever secured to the furnace housing and that secured to the furnace head are both arranged to be encircled in a plane common to them by a flange having a ledge fastened thereto, through an intermediary layer of insulating material.
 2. A device for securing a furnace head to the housing of a reduction furnace, for example a calcium carbide furnace, the upper rim portion of the furnace housing being arranged to be encircled by a cantilever receiving a layer of insulating bricks to provide support for the water-cooled furnace head, wherein the furnace head is designed to have a cantilever running parallel to an opposed cantilever fast with the furnace housing, whereby the cantilever secured to the furnace housing and that secured to the furnace head are both arranged to be encircled in a plane common to them by a flange having a ledge fastened thereto, through an intermediary layer of insulating material.
 3. The device as claimed in claim 1, wherein the flanges are arranged to have a common vertical plane.
 4. The device as claimed in claim 1, wherein the flanges are arranged to have a common horizontal plane.
 5. The device as claimed in claim 1, wherein the ledge has a rectangular cross-sectional area and substantially the same overall thickness.
 6. The device aS claimed in claim 1, wherein the ledge is made up of elastic resilient material within the area between the cantilever secured to the furnace housing and that secured to the furnace head, the ledge having a smaller cross section within that area than within the reach of the flanges.
 7. The device as claimed in claim 1, wherein the area between the cantilever secured to the furnace housing and that secured to the furnace head is left free from insulating material.
 8. The device as claimed in claim 1, wherein a resilient elastic plate is arranged within the area between the cantilever secured to the furnace housing and that secured to the furnace head.
 9. The device as claimed in claim 1, wherein the flanges, the insulating intermediary layer and the ledge comprise a plurality of parts and have a polygonal cross-sectional area, seen in the direction of the furnace axis.
 10. The device as claimed in claim 1, wherein the flanges, the insulating intermediary layer and the ledge are connected together by means of insulating bolts. 